Electrochemical potential of Microgramma vaccinifolia rhizome lectin

Abstract

This work reports the isolation of Microgramma vaccinifolia rhizome lectin (MvRL) and the determination of electrochemical potentials of MvRL in the presence of Ca2+, Mg2+ and human type O erythrocytes. MvRL showed the highest specific hemagglutinating activity with human type O erythrocytes and showed a single polypeptide band of 17kDa on SDS-PAGE. MvRL hemagglutinating activity was neutralized after dialysis with EDTA, and addition of Ca2+ and Mg2+ restored the activity. Electrochemical potentials of MvRL in the presence of 100mM Ca2+ (882mV) and 60mMMg2+ (1051mV) were higher (p<0.05) than in the presence of only 0.15M NaCl (247mV), indicating that the electrochemical system was sensitive to structural and physico-chemical changes promoted by these ions. MvRL potential did not change in the presence of type O erythrocytes. The electrochemical system was able to detect changes in electrochemical potentials of MvRL promoted by Ca2+ and Mg2+, even in a complex environment (human serum supplemented with 40 and 60mM of these ions). The study reveals that the stimulatory effect of Ca2+ and Mg2+ on hemagglutinating activity may be linked to conformational change and/or alterations in surface charge distribution of MvRL.